The aim of this research proposal is to explore memory systems in HIV. In the last decade, important advances have been made in the domain of HIV and cognition, and research has focused mainly on injury to the basal ganglia and associated fronto-striatal systems. However, little is understood about the effects of the virus on other brain systems, especially those that when disrupted, often result in dementia. The proposed study has two specific aims. First, functional MRI will be employed to examine the functional integrity of hippocampal-prefrontal networks in the illness. Second, volumetric analysis of the hippocampus will be conducted using structural MRI methodology. This proposed multi-dimensional study represents the first formal investigation of hippocampal-prefrontal networks in HIV, and will therefore extend clinical understanding of the structural and functional changes that occur in the context of HIV infection. [unreadable] [unreadable] [unreadable]